The majority of medical ultrasound examinations/procedures are carried out using “general purpose” ultrasound machines, which produce images of a selected portion of the human body. These images are in turn interpreted by a trained specialists in ultrasound. Radiologists, sonographers and, in some cases, specially trained physicians, usually in certain specialties, are among those who are trained to read and interpret an ultrasonic image. The cost of a general purpose ultrasound machine, however, is quite high, as is the cost of interpretation. Accordingly, an ultrasound procedure is typically quite expensive. This cost factor inherently limits the use of ultrasound, even though it is potentially a widely applicable, non-invasive diagnostic tool.
An alternative to the general purpose ultrasound machine is an application-specific ultrasound device. With an application-specific device, instead of using a general purpose ultrasound machine, a single type of ultrasound procedure is accomplished. There are many examples of application-specific or single purpose ultrasound machines. Two examples are shown in U.S. Pat. Nos. 4,926,871 and 5,235,985, both of which are directed toward a device for measuring the amount of urine in the bladder.
Instead of producing a real-time image which must be interpreted by a skilled operator, by measuring the image and then calculating the volume, the application-specific apparatus uses ultrasound signals and follow-on signal processing to automatically locate the bladder within the overall ultrasound volume, determine its boundaries, and then automatically compute the bladder volume, which is then provided to the trained, but not ultrasound skilled (e.g. sonographer), operator.
While bladder volume, of course, can be determined using a general purpose machine, as indicated above, an application-specific machine itself produces an actual volume number. This approach not only decreases the time to produce a bladder volume determination, it is also typically more accurate, and certainly less expensive. It does not require the services of an ultrasound-skilled operator, because the machine itself automatically produces the desired bladder volume information once the ultrasound probe (transmitter/receiver) has been properly positioned.
Application-specific ultrasound devices significantly lower the cost of ultrasound examinations and thus can be regularly used for a single patient in order to track bladder volume information over an extended period of time. This has proved to be extremely useful in both diagnosis and treatment of bladder dysfunction.
There are many other examples of application-specific ultrasound machines. These include machines which determine abdominal aorta size and kidney volume, among others. The significant disadvantage of application-specific ultrasound machines is that they are, in fact, just that—useful for just a single application. It would be too expensive and too cumbersome for a physician, particularly a general practitioner, to maintain a large number of application-specific ultrasound machines, even though ultrasound is useful in a variety of diagnostic situations.
Accordingly, it would be desirable to have an ultrasound system which is inexpensive, reliable and which does not require a specially trained operator and which further can be used in a variety of diagnostic situations.